The present invention is directed to data terminal devices in general and more particularly to the keyboard of the terminal devices. A business that has emerged in recent years is the fast food industry wherein the employees both manufacture and sell the product. The working environment in which this business is usually carried out includes the passage of food over a counter to a customer. The data terminal device which is used as part of the business transaction is normally positioned on the counter. Accidental spillage of drinks and food on the keyboard of the terminal device are regular occurences in this type of business environment. In addition, menu changes occur from day to day and in some instances during the same day requiring that the captions on the keys of the keyboard be changed. This latter problem has been solved in the prior art by providing a flexible member which is positioned over the control keys of an accounting machine, the flexible member containing indicia bearing areas which are located substantially identical with the control keys of the accounting machine to change the classification of the control keys. This arrangement is shown in U.S. Pat. No. 2,625,330 issued to K. M. Buckey et al. and assigned to the assignee of the present application. Such type of structure has been found not to work well on those keyboards where the keys are mounted in close proximity to each other, since depression of a portion of the flexible member will normally result in more than one control key being depressed. In view of the above problems, the principal object of the present invention is to provide a keyboard member which will prevent liquids from entering the keyboard of a terminal device and would be adaptable for changing the key classification indicia on the keyboard. Another object of this invention is to provide an auxiliary keyboard wherein the keys of the keyboard are constructed to be slidably mounted in the keyboard but incapable of falling out of the keyboard when the keyboard is in an inverted position. It is a further object of this invention to provide an auxiliary keyboard which is lightweight and low in cost.